The subject invention relates to a thin light managing system, and more particularly, to a thin light managing system for redirecting and redistributing light from one or more light sources.
Conventional light managing systems for automotive vehicle headlights, sidelights and taillights typically include a bulb filament recessed in a reflector housing behind a cover lens. The light emitted from the bulb filament is reflected from the reflector housing outwardly through the cover lens to form a beam or planar light image. The cover lens shapes the light into the desired pattern, i.e., focused headlight beam or pattern side or rear signal. However, conventional bulb and reflector lighting systems are disadvantageous in terms of styling and size flexibility. The bulb and reflector require a significant depth and width to acquire desired focus and light dispersion through the cover lens, thus, limiting the ability to streamline and contour the light system.
Other systems have been developed to provide alternatives to the conventional bulb filament and reflector system utilizing a light pipe and collimator to direct the light to a reflective emitter having a plurality of lens facets to redirect the light in the desired path and pattern. These systems are exemplified in U.S. Pat. No. 5,434,754 to Li et al., issued Jul. 18, 1995 and U.S. Pat. No. 5,197,792 to Jiao et al., issued Mar. 30, 1993.
However, there is still a need for an efficient, thin light managing system which provides the flexibility of coupling a variety of light emitting arrangements for both direct lighting and redirected lighting by combining the use of direct lensing and light pipe optics having redirecting facets to achieve a desired light distribution and pattern.
The present subject matter relates, in part, to a system for redirecting and/or redistributing light from one or more light sources to provide lighting design flexibility and to accommodate lighting packaging restrictions. The system employs a unit cell approach whereby one or more light sources, preferably light emitting diodes, or LEDs, are coupled with an optics structure. A plurality of unit cells, which may be of either a lensing or light pipe variety, can be coupled in a variety of arrangements to achieve the desired light distribution and intensity patterns.
The tensing unit cells employ a lensing structure whereby light incident upon the unit cell is transmitted directly there through, typically after having been reconditioned in some fashion. Examples include Fresnel, concave, or convex lens structures. A unique dual surface lens element employing spherical and cylindrical surfaces, a specially tailored Fresnel lens element, and a combination Fresnel/pillow lens element for achieving desired light distributions are disclosed.
Light pipe unit cells include a light transmitting structure that redirects and redistributes light incident thereupon, typically by employing light coupling optics and redirecting facets formed on a surface of the structure.
The system is particularly advantageously adapted to vehicle signal lamp applications. For example, signal lamp intensity distribution requirements in the United States are defined by Federal Motor Vehicle Safety Standard (xe2x80x9cFMVSSxe2x80x9d) No. 108. FMVSS 108 is consistent with other regional standards and unique customer requirements. Unit cells can be constructed, configured, and oriented so as to meet any of these requirements for substantially any given signal lamp size, shape, or configuration in a mechanically robust structure. In addition, the design and packaging flexibility afforded by the present system can provide the opportunity to improve upon conventional vehicle signal lamp configurations.
The system is particularly thin. It may be employed in packaging configurations ranging from around 25-50 mm. The flexibility afforded by the unit cell approach simplifies packaging in vehicles and allows for lighting design and packaging variations, e.g., signal lamps with surface curvatures.
The system is cost effective because the unit cell approach simplifies lighting design; each unit cell constitutes an optical design element which may be advantageously varied and configured with other such design elements to cost effectively achieve a desired light intensity distribution.
Advanced light sources, such as LEDs, are cooler, consume less power, and are more reliable and durable than conventional filament light elements. Moreover, LEDs reach full light intensity virtually instantaneously, whereas conventional filament light elements take a finite period of time to reach full intensity. An automobile traveling at highway speeds will travel a significant distance in the time it takes the filament element to reach full intensity. Accordingly, when incorporated in vehicle signal lamps, such as brake lights, LEDs provide safety advantages because they can deliver the xe2x80x9cbrake signalxe2x80x9d more quickly than signal lamps employing conventional filament-based lighting elements.
The light management system employing unit cells enable styling enhancements such as logos"", decals, or script. In addition, the unit cell approach enables the creation of unique illuminated appearances, or patterns, not possible or practical with conventional light sources and associated optics.
A variety of different types of unit cells may be combined to achieve a desired design and intensity distribution or to meet packaging restrictions. The resulting optics structure, which may comprise a variety of optic shapes and surfaces, is preferably formed from an optics grade plastic material.
According to another aspect of the present invention, plastic optics structures can be formed by a unique injection-compression molding technique. One or more molding parts define an injection cavity and each molding part may include a movable surface portion for compressing material within that molding part. Each compressible molding part is preferably independently controlled so as to apply a specified amount of force, to compress a specified distance, and to compress for a specified duration of time.
A molding assembly according to the present invention, comprising one or more such independently controlled compressible mold parts, enables the molding of optics structures having complicated geometries, including thick and thin portions in the same relative area and significant transitions from one geometry to the next, with true and accurate surfaces. Accordingly, the complicated optics structures of the present invention can be economically produced, even for the high volumes required for the auto industry, with great accuracy. Thus, the optics system of the present invention represents a commercially viable improvement in lighting technology.